Commercial enterprises (e.g., companies) and others gather, store, and analyze an increasing amount of data. The trend now is to store and archive almost all data before making a decision on whether or not to analyze the stored data. Although the per unit cost associated with storing data has declined over time, the total costs for storage has increased for many companies because of the volumes of stored data. Hence, it is important for companies to find cost-effective ways to manage their data storage environments for storing and managing large quantities of data.
In response, data storage drive (e.g., magnetic hard disk drive) manufacturers have increased data storage capacity by using various innovative techniques, including increasing the number of platters and the density of tracks and sectors on one or both surfaces of the platters. A platter is commonly a circular disk having one or both sides of a rigid substrate coated with a magnetic medium, on which data is stored. Data storage devices typically have several platters that are mounted on a common spindle. Each side on which data is stored commonly has an associated read head and a write head, or sometimes a common read/write head. The platters are rotated rapidly within the data storage device about the spindle, and an actuator moves heads toward or away from the spindle so that data can be written to or read from tracks. A track is a circular path on the magnetic surface of the platters. One way of increasing data storage capacity is to have very narrow tracks and to place heads very close to the surface of the platter, e.g., micrometers (also, “microns”) away. However, because it takes more energy to write data than to read data (e.g., because the magnetic surface of platters must be magnetized to store data), data storage drive manufacturers inserted a buffer track between tracks storing data so that a wider track can be written to than read from. The buffer tracks could be magnetized when tracks on either side of the buffer tracks (“data tracks”) were written to, but read heads would only read from data tracks and ignore buffer tracks. However, buffer tracks decrease available space on platters.
To avoid wasting space on buffer tracks, a new technique employed by the industry is shingled magnetic recording (“SMR”). SMR is a technique to increase capacity used in hard disk drive magnetic storage. Although conventional data storage devices as described above record data by writing non-overlapping magnetic tracks parallel to each other, SMR involves writing new tracks that overlap part of the previously written magnetic track, leaving the previous track thinner, thereby allowing for higher track density. The SMR tracks partially overlap in a manner similar to roof shingles on a house. Shingled magnetic recording is expected to increase hard disk capacity by about 25% as compared to non-shingled storage.
However, if there exist hostile environmental events, e.g., vibrations, mechanical shocks, etc., use of SMR could lead to increased data corruption as compared to existing write techniques because not only could data in the track being written to become corrupt, but possibly also data in previously written adjacent tracks.